feat(desktop): optional wipe-on-close (Settings -> Sicherheit)

apps/desktop/src/lib/memoryWipeSettings.ts

@@ -0,0 +1,24 @@
+// Persisted toggle for the "wipe local caches on app close" feature.
+// Read by SecurityCenter (UI) and AuthContext (renderer-side IPC handler).
+//
+// Stored in localStorage so the preference survives sessions without
+// touching the secret-store or SQLite. The key is on the preserve
+// whitelist in lib/memoryWipe.ts so a sign-out wipe (or a closing wipe)
+// doesn't blow away the user's own preference.
+const KEY = 'chatapp.wipeOnClose.v1';
+
+export function isWipeOnCloseEnabled(): boolean {
+  try {
+    return window.localStorage.getItem(KEY) === '1';
+  } catch {
+    return false;
+  }
+}
+
+export function setWipeOnClose(enabled: boolean): void {
+  try {
+    window.localStorage.setItem(KEY, enabled ? '1' : '0');
+  } catch {
+    /* ignored */
+  }
+}